1. Field of the Invention
The present invention involves Epstein-Barr Virus (EBV) transformed cells which have been superinfected with a second virus and which, while expressing components of exogenous virus on their surface, do not release extracellular virus of the superinfecting strain. More particularly, the present invention relates to a cell line transformed by EBV which contains the EBV genome in a latent state; these cells superinfected by the HTLVIII strain of the human immmunodeficiency virus (HIV) give rise to a population of cells which do not release extracellular HIV, but which form syncytia when cocultivated with lymphocytes permissive for HIV. These syncytia are inhibited by antibodies to HIV.
2. Background Information
The human immunodeficiency virus is an essential element in the causation of acquired immune deficiency syndrome (AIDS). Cell to cell transmission of HIV with syncytia formation is believed to play an important role in dissemination of this virus throughout the body.
With the ever increasing number of reported AIDS cases, there is great need to more accurately determine the severity of the disease. Furthermore, there is a need to measure functional antibodies in vaccine recipients, without the use of possible infectious antigens.
K. Dahl, K. Martin and G. Miller, "Differences Among Human Immunodeficiency Virus Strains in Their Capacities To Induce Cytolysis or Persistent Infection of a Lymphoblastoid Cell Lines Immortalized by Epstein-Barr Virus", Journal of Virology, Vol. 61, No. 5, 1602-1608, May 1987 described the use of the X50-7 line of human umbilical cord lymphocytes immortalized by EBV and infected with HTLV-IIIB to form cell line LL58, which released extracellular HIV.